Toshiba e-STUDIO 160 Service Manual page 52

(5) Development
• "Developing" is the process of converting the
electrostatic latent image to an image vis-
ible to the human eye.
The developing agent is fed to the surface of the photosensitive drum by the magnetic rollers, and
impressed on the rollers. Toner in the developer agent attaches to areas on the photosensitive drum
having a potential lower than the developer bias (reverse developing method).
Magnet
Sleeve
Bias voltage
-460V or -430V
03009
• Switching of developing bias polarity
Fogging is reduced by switching the bias of negative
polarity (approx. +150V).
• About Developing Agent
Toner and carrier are mixed. The toner is
charged to minus polarity, and the carrier is
charged to plus polarity by friction caused
by stirring.
Toner: Comprises plastic and Magnetite.
Carrier: Ferrite
e-STUDIO160/200/250 COPYING PROCESS
Carrier
(Always attracted
on to the magnet)
When the
of the photosensitive
drum is higher than the
developer bias:
Toner
When the
of the photosensitive
drum is lower than the
developer bias:
Fig. 3-2-8
Drum
White background
White background
potential
600V
460V
or
430V
300V
potential
200V
100V
0
Resin
(35 ~ 60 %)
[Toner]
3 - 4
Fig. 3-2-7
Intermediate tones
Image is not developed
by bias potential.
Image is developed by
toner.
Fig. 3-2-9
voltage charged areas to positive
Magnetite
(40 ~ 65%)
5 ~ 20 µm
[Carrier]
Fig. 3-2-10
December 2002 TOSHIBA TEC
Sleeve roller
03008
Black solid
Bias
voltage
03009-a
Ferrite
Approx. 60 µm